1. Field of the Invention
The present invention relates to a novel and useful optically active aromatic carboxylic acid derivatives represented by the following formula (I) and the processes for producing such derivatives.
Such optically active aromatic carboxylic acid derivatives, let alone their preparation process, have been totally unknown in the art.
2. Description of the Prior Art
E. D. Bergmann, J. Org. Chem., 24 549 (1959) describes the compound represented by the general formula, ##STR3## which is, however, racemic compound and not disclosed or any practical application at all.
In addition, said compound cannot be utilized as an intermediate of a ferroelectric liquid crystal compound because of being racemic compound, whereas the compound of the present invention can readily be derived to such a ferroelectric liquid crystal compound.
For example, the following prior art (I') is a process for preparing an optically active aromatic carboxylic acid derivative by means of introducing an active alkyl group into phenol, and the prior art (II') is that by means of ethyl-etherification by applying ethanol and an alkali to .alpha.-bromoethyl group of the benzene carboxylic acid, whereas the present invention is a process for obtaining an optically active aromatic carboxylic acid derivative by alkylating an optically active alcohol obtained from asymmetric hydrolysis of the corresponding racemic ester and then debenzylating or de-(lower) alkylating. Since said optically active alcohols has the asymmetric carbon atom directly bonded to benzene ring, needless to say, the produced aromatic carboxylic acid derivatives become optically active. Accordingly, the process of the present invention is entirely different from the prior art processes. ##STR4## wherein l is 1 or 2 and * indicate asymmetric carbon atom. ##STR5##